Fits Ford Tractor Models NAA, 501, 541, 600, 601, 611, 620, 621, 630, 631, 640, 641, 650, 651, 660, 661, 671, 681, 700, 701, 740, 741, 771, 800, 801, 811, 820, 821, 840, 841, 850, 851, 860, 861, 871, 881, 900, 901, 941, 950, 951, 960, 961, 971, 981, 2000 4-cylinder, 2031, 2111, 2120, 2131, 4000 4-cylinder, 4031, 4120, 4121, 4131.